It is known in the art to have an engine power a vehicle drive transmission and also an auxiliary pump in an auxiliary hydraulic circuit. When the engine is at idle, such as when the vehicle is stationary, there can be operation of the auxiliary hydraulic system and, at the time of such operation, the engine speed is caused to increase. Controls for increasing engine speed have included mechanism operable simultaneously with manual operation of a valve in the auxiliary hydraulic circuit and systems which respond to pressure within the auxiliary hydraulic circuit.